Determination of sample size for various study designs in medical research: A practical primer.

Formulating a research question and selecting an appropriate study design for answering that question are crucial initial steps in the research process. The population, intervention, control group, and outcomes measures (PICO time and setting [TS]) framework provides a practical guide in this regard, which stands for population, intervention, control, outcome, type of research question, and study design. The various study designs have their own merits and demerits, and implementing the methodology meticulously requires knowledge of all of these. Similarly, different methods of sample size calculation are warranted based on the most appropriate study design and outcome variables of interest. Sometimes, a post hoc power analysis can be performed after the sample size calculation, to check whether the study was adequately powered or not. There are multiple validated free software tools for sample size calculation, including Open-Epi, R, StatCalc, etc. The practice by most researchers of reporting significant P values is to be replaced by reporting effect sizes, as the latter is a much better estimate of the strength of association. This review provides a comprehensive, ready reckoner for busy family physicians to quickly identify the appropriate study design for answering any applied research questions in their minds and estimating the sample size required for the same.

Early prognosis prediction in acute myeloid and acute lymphoid leukemia patients using cell-free DNA concentration ratios.

Background: Cell-free DNA (cfDNA) is a promising biomarker for disease prediction in many cancers, including acute leukemia (acute myeloid leukemia [AML] and acute lymphoblastic leukemia [ALL]). This study investigated the role of cfDNA in predicting relapse or unfavorable outcomes in acute leukemia patients upon initial diagnosis. Methods: Paired peripheral blood samples of 25 patients with ALL and AML were compared at baseline and induction/follow-up and clinically correlated with clinicopathological and outcome variables according to the risk category. cfDNA was isolated using commercial cfDNA extraction kits. The probability of poor outcomes in high-risk groups and a cut-off value for risk stratification minimal residual disease (MRD) positivity and outcome prediction were derived. Results: Twenty-five patients diagnosed with AML and ALL were risk-stratified based on NCI risk stratification, and of these 25 patients, 4 patients were of standard risk (SR) and 1 patient was of intermediate risk (IR), while a majority of patients (80%) were of high risk (HR). Of these, four HR patients passed away. The ratio of cfDNA reduction at baseline and the end of induction was a strong predictor of poor outcomes in high-risk patients, regardless of the MRD status. A cfDNA ratio score of 2.6 or higher at diagnosis/remission predicted poor outcomes, with higher accuracy than conventional MRD detection by flow cytometry. Conclusion: A higher cfDNA ratio at diagnosis/remission or at baseline predicts poor outcomes in acute leukemia patients. This pilot study suggests that cfDNA ratio scoring may be a useful tool for predicting prognosis in acute leukemia patients, regardless of the MRD status.

Primary mediastinal hemangiopericytoma treated with preoperative embolization and surgery.

Hemangiopericytomas are rare tumors originating from vascular pericytes. The mediastinum is an extremely uncommon site with only a few cases reported. Diagnosis is based on histopathology and immunohistochemistry, which differentiates them from synovial sarcoma and solitary fibrous histiocytoma. They have a variable malignant potential. Treatment is mainly surgical extirpation as the role of adjuvant therapy is controversial. Preoperative embolization has been sparingly used. We report a case of primary mediastinal hemangiopericytoma in a 47-year-old man treated successfully with preoperative embolization and surgery.

Spinal polyostotic fibrous dysplasia in two adults: Does only biopsy unravel the mystery?

Polyostotic fibrous dysplasia is a rare non-inheritable genetic disease due to mutation in GNAS gene. Here we present two adults who were accidentally detected lytic lesions in spine and after extensive evaluation for malignancies; was diagnosed on biopsy. Current concept of the disease and management is discussed.

Sarcomatous transformation (Leiomyosarcoma) in polyostotic fibrous dysplagia.

Malignant changes in polyostotic fibrous dysplasia are very rare. Most common malignancies reported are osteosarcoma and fibrosarcoma, chondrosarcoma and malignant fibrous histiocytoma. Here, we report a previously diagnosed case of fibrous dysplasia who has developed leiomyosarcoma; diagnosis of which was delayed for about one year despite repeated fine needle aspiration and open biopsy.

Clinical spectrum of hypopituitarism in India: A single center experience.

OBJECTIVES: There is paucity of information regarding clinical profile of hypopituitarism from India. We report the clinical profile of hypopituitarism from a tertiary center in North India. MATERIALS AND METHODS: This study was carried out in patients attending our endocrine center between January 2010 and December 2011. All new patients were studied prospectively and those registered before January 2010 retrospectively. Relevant clinical, hormonal, and imaging data were collected. Dynamic testing for pituitary functions was carried out as necessary. Hormonal deficiencies were defined as per prevailing recommendations. RESULTS: This study included 113 subjects. The mean age was 38.6 ± 17.8 years (range, 4 - 76 years). There were 78 (69%) males and 35 females (31%). There were 22 subjects aged ≤18 years (childhood and adolescence) and 91 adults (>18 years). Visual disturbances were the most common presenting complaint (33%), though headache was the most common symptom (81%). Fifteen percent presented with pituitary apoplexy. Tumors comprised of 84% of cases. Hypogonadism (97%) was the most common abnormality seen followed by hypothyroidism (83.2%), hypoadrenalism (79.6%), growth hormone deficiency (88.1% of the 42 patients tested), and diabetes insipidus (13.3%). Panhypopituitarism was seen in 104 (92%) patients. There were no cases of hypopituitarism secondary to traumatic brain injury, subarachnoid hemorrhage, central nervous system infections, or cranial irradiation to extrasellar tumors. CONCLUSION: The most common cause of hypopituitarism at tertiary care center is pituitary tumors and the commonest presenting complaint is visual symptoms. Panhypopituitarism is present in 92% cases.

Childhood adrenocortical carcinoma: Case report and review.

Adrenocortical cancers in childhood are very rare tumors. The tumors have varied presentation - either virilizing forms or presentation with Cushing's syndrome, or both. In children, due to the rapid development of symptoms they come to attention early, however, if not diagnosed and treated early can have a downhill course. The last decade has seen the emergence of new diagnostic imaging modalities. There is also intense ongoing research in newer treatment modalities as these tumors can be unresectable or have a high recurrence rate.